Repeating fuse construction



Dec- 22, 1942- w. o. scHuLTz E-rAL l 2,305,996

REPEATING FUSE CONSTRUCTION Filed May 25, 1940 '3 sheets-sheet 1 Dec.22, 1942. w. o. scHULTz ET Al. 2,305,996 REPETING' FUSE CONSTRUCTIONFiled May 25, 1940 3 Sheets-Sheet 2 A ORNE.

Dec. 22, 1942. w. o. SCHULTZ ET AL 2,305,996

REPEATING FUSE CONSTRUCTION Filed May 25, 1940 3 Sheets-SheerI 3Patented Dsc. 22, 1942 UNITED STATES PATENT OFFICE 2.305.996 maniac rosaooNs'rauc'rroN William 0. Schultz, South Milwaukee, and Alwin G.Stcinmayer, Milwaukee, Wis., mignon to Line Material Company, 'SouthMilwaukee, Wis.,

a corporation oi Delaware Application May z5, 1940, serial No. 337,19514 claim. (c1. zoo- 126) This invention relates to a repeating fuseconstruction and is particularly directed to a construction in which adevice is provided whichl recloses the circuit after the blowing oi' afuse and connects a fresh or reserve fuse in vthe circuit, such devicebeing capable of repeating as many times as the device is designed for.

The advantage of this automatic repeating fuse construction is that thedevice lends itself to transmission service and customers substationservice. Frequently in theseservices short-circuits occur due to any oneof many causes, such as a tree falling across alpair o1' lines, a pairof lines being whipped together by a wind, a fiashover, a temporaryground, or the branch of a tree which in a violent wind may be blownagainst the line. Under these and similar conditionsv it frequentlyhappens that the trouble is only temporary and that it either' ceases ofitself or the fault is burned out almost immediately.

This invention is designed to provide a device which will take care ofconditions such as outlined above, which will electrically disconnectthe blown fuse from the line, and after a predetermined brief intervalimmediately connect a reserve or fresh fuse in the line, such deviceproviding for the successive operation of as many fuses as the device isequipped to handle, and to provide a device of this type in which thetime delay interval is obtained by an automatic time delay device.

Further objects are to provide a construction in which the device iswell suited for high voltage lines, in which each fuse as it blows dropsdownwardly and swings outwardly clear of the upper contact to therebyprovide maximum spacing at the open portion of the circuit, and in whichswitch mechanism is provided for connecting the succeeding fuse, theswitch mechanism being so constructed that when open a wide spacing isobtained between the contacts of the switch, and in which the switchcloses with a quick iinal motion so that arcing even under heavy loadconditions is minimized.

This invention provides for the renewal of a blo-wn fuse withoutinterrupting the service, and objects of this invention are to provide aconstruction which permits the ready removal and refusing of the blownfuse, which permits the ready restoring of such refused fuse, and theautomatic disconnecting of the next adjacent auxiliary or reserve fuseWithout at any time interrupting the circuit during this restoringoperation.

Further objects of this invention are to provide a construction in whichno fuse has to be first mechanically moved into place before it is readyto operate upon the blowing of a preceding or iirst fuse, in which theauxiliary or reserve fuses although mechanically in place are never-.theless automatically electrically connected in service in successionas the preceding fuse or fuses blow.

Further objects are to provide a drop-out fuse construction of therepeating fuse type in which the several fuse units are so made thatpositive contact is maintained between the stationary contact of thehousing and the contact carried by the fuse tube, which ultimately movesaway from the stationary contact, such positive contact being maintainedfor an appreciable interval of time to insure complete clearing of thefuse tube prior to the breaking of the contact between one of the fusetube contacts and one of the contacts carried by the housing, thusguarding against any possibility of arcing at this point.

Further objects are to provide for the quick withdrawal of the fuse linkprior to the interruption of the circuit between the stationary contactand one of the contacts of the fuse tube so that the chance of arcing atthis point is minimized, and in which means are provided which inaddition to the action of gravity afford positive means for moving thefuse tube bodily out of service.

Further objects are to for repeating fuses in provide a constructionwhich the blown fuse may be readily removed by a switch stick and may bereadily replaced after refusing by such switch stick without requiringthe lineman to handle any portion of the fuse structure while it is'connected to either side of the high tension circuit. Further objectsare to provide a repeating fuse construction in which upper and lowerstationary contacts are provided for the several fuses, in which thetransfer switches for connecting successive fuses are located adjacentclosed upper ends of the fuse tubes at a position remote from the openlower ends thereof so that the blast'from the open lower ends is at azone far removed from the transfer switches and so that there is nochance of the whipping of any remaining portion of the fuse link intoaccidental damaging contact with another of the fuse devices.

Further objects are to provide a construction in which a simple type ofmechanical escapement mechanism is provided for the time delay means, in-which the time delay means is housed and protected from sleet, rain andsnow, vand in which o the accompanying drawings, in which:

Figure l1 is a side elevation, with parts sectioned on?, showing one ofthe fuse umts and the associated transfer switch mechanism, such viewcorresponding to a section on the line i'i of Figure 2.

Figure 2 is a face view of the device with one of the fuses removed..

Figure 3 is a sectional detail of the upper portion of one of the fuseconstructions showing it while a refused fuse unit is being rocked backinto place and just before it has been completely rocked back intoplace.

Figure 4 is a sectional view on the line 4 4 of Figure "1, such viewbeing extended laterally so as to show the gear train more clearly.

Figure 5 is a fragmentary view showing a further form of escapementdevice.

Referring to the drawings, it will be seen that the repeating fuseconstruction comprises a rear supporting member i which is provided witha transverse upper channel member 2. This channel member carries aplurality of spaced insulators 3, 4 and 5, three having been shownthough any number may be employed depending on the number of fuse units.The lower end of the member I carries an insulator 3 which supports atransversely extending conducting ba 1 to which the lower stationarycontacts 3, 3 and Ill are rigidly attached.

The lower stationary contacts are duplicates and comprise thehook-shaped spaced fingers il which preferably have an overhanglngportion I2 and which are provided with brush contacts i3.

'Ihe drop-out fuse units are all of similar construction and comprise ineach instance a fuse tube I4 which is provided with a collar i! near itslower end, such collar being provided with a projecting arm i6 adaptedto be received by a suitable portion of a switch stick in a well knownmanner during removal and replacing of the fuse tube. A lever l1 ispivoted at its upper end to the collar II and its lower end is providedwith laterally projecting trunnions i3 which removably seat within thehooks ii of the lower stationary contact. The lever I1 is provided witha suitable clamping means as indicated at I3 for clamping the end of thefuse link in place. The upper end of' the fuse tube is provided with anupper contact 2i which terminates in a threaded neck which receives theupper cap 22, such upper cap being provided with an upwardly projectingpin 23 adapted to be received by a latching member hereinafterdescribed.

The upper contact carries an eye 24 which is pivoted at 25 and springurged to the position shown in Figure 1. This eye is rigidly clampedwith a pair of fingers 26 located on opposite sides of the upper contact2| of the fuse tube so that when the eye is pulled downwardly by aswitch stick, it will raise the latch 21 which latter is pivotallycarried by the upper stationary contact indicated generally at 23.

All of this construction is similar to that shown in our prior FatentNo. 2,176,227 of October 17, 1939. The upper cap 22 as shown in theprior patent is for the purpose of clamping the upper buttonhead of afuse link of any suitable type. such for example as that shown in theabove mentioned patent, the fuse link preferably having a fusiblesection as shown in the patent adjacent its upper end and having aflexible leader extending therefrom and clamped by the thumb nut orother clamping means I 3 to the lower lever i1. The upper stationarycontact is also provided with a brush contact 2l which bears outwardlyagainst the fiat face 30 of the upper contact 2i of the fuse tube.

The latch 21 is generally channel-shaped and is provided with acam-shaped upwardly slanting outer end 3i beneath which the pin 23 ofthe upper contact of the fuse tube rides when the fuse tube is rockedback into service after refusing. The latch is provided with ashouldered portion as shown in Figure 1 which hooks in front of the pin23 and thus retains the fuse tube against outward dropping motion undernormal conditions.

When the fuse blows, the fuse link is ruptured and releases the lever i1allowing the lower end of the fuse tube to rock downwardlyand outwardlyand withdrawing the pin 23 from engagement with the latch and thusallowing the fuse tube to rock outwardly and downwardly at its upperend, as shown in Figure 3. This rocking motion continues until the fusetube rocks downwardly to an inverted position.

In order to prevent the latch 2 1 from rocking downwardly below apredetermined point when out of engagement with the fuse tube, suchlatch is provided with a rearwardly projecting tongue 32, see Figure 3,which seats beneath a shoulder formed on the terminal 23.

It is to be noted that al1 of the bottom stationary contacts areelectrically connected to the conducting bar 1 and that each of theupper stationary contacts is insulated from every other upper contactunder normal conditions. One line wire connects to the upper left-handterminal in any suitable manner not shown, and the other line wireconnects to the conducting bar 1 in any suitable manner not shown. Thecircuit, therefore, is closed through the left-hand fuse under normalconditions and when this fuse is ruptured, it drops downwardly andoutwardly as described hereinabove and thereafter an automatic transferswitch comes into operation which connects the second upper terminalmember to the first upper terminal member, as shown in Figure 2. Anautomatic transfer switch mechanism is provided for all except the lastupper terminal member so that as successive fuses blow,

the upper line terminal is connected successively l to the upperterminal members. Obviously as many units may be employed as desired,three having been shown as illustrative.

The automatic transfer switch mechanism comprises a switch arm 33 whichcarries a switch blade or bar 34. 'I'his switch blade or bar may befreely floating if desired and connects the contact arm 35, electricallyconnected to the upper terminal of the first fuse, to the contact arm orbar 3B electrically connected to the second upper terminal.

The second upper terminal is provided with a contact arm 31 which isadapted to be connected by the corresponding contact bar 3l of the nexttransfer switch to the upper contact arm 33 of the third upper contact.Each of these upper the flat face 30 of the upper contact 2| of thecorresponding fuse tube. The divergent lips 4I do not engage or grip thefuse tube but mere- `ly act as guides when the fuse tube is being rockedback into place, as shown in Figure 3.

The switch arms are associated with time delay mechanism of themechanical escapement type. 'Ihe switch arms and the time delaymechanism are identical. Each switch arm is-,provided with a rearwardlyprojecting extension 42 which is provided with a circular face 43concentric with the pivot pin 44 about which the switch arm rocks. Thisextension 42 is also provided with a cam face 45 which extends in anysuitable manner, for example, radially outwardly as shown in Figure l.

'I'he switch arm is urged towards switch closed position by means of thespring 46 and the switch arm may be provided with a housing 46' at leastpartially surrounding the spring 46 as shown in Figure l. It isrestrained Ifrom closing motion by the engagement of the portion 4| withthe face 38 of the upper contact of the fuse tube. In other words, aportion of thel fuse tube itself engages a part of the switch arm andrestrains the switch arm from closing as long as the fuse tube is inservice. When the fuse tube drops out of service, either upon overloador when it is manually removed as previously described, the

switch arm closes and connects the next adjacent fuse in service.Obviously when a blown fuse is refused and is rocked back into position,it automatically opens the switch. Opening of the switch does not occuruntil after the contact 4l of the switch arm engages the upper contact2| of the fuse tube being rocked back into service and thus there is nobreak in the service when a refused fuse is rocked back into serviceposition.

The mechanical escapement time delay device may comprise a train ofgears, the rst of which 41 is rigidly attached to .a projecting arm orswitch restraining member 48, both of which are rigid with the shaft 49as shown most clearly in Figure 4. The member 48 is in the path oftravel of the extension 42' of the switch arm, see Figure 1, so thatwhen the switch arm rocks upwardly when released by the outward droppingof the corresponding fuse tube, it operates the time delay mechanism bydriving the shaft 43 through engagement between the members 42 and 48.

Mechanical escapement means are provided for delaying the rotation ofthe shaft 49, as will switch arm is no longer restrained and thus makesa quick closing stroke, thus avoiding arcing during closing.

The extension 42 with the faces 45 and 43 constitutes a cam and suchmember, together with the member 48, constitutes the mechanism wherebythe time delay device is driven from the spring or biasing means 46 ofthe switch.

The shaft 49 is provided with a spring 50 which tends to drive themember 48 in a counterclockwise direction, as viewed in Figure 1, suchspring being shown in Figure 4 and constituting restoring means forrestoring the time delay mechanism to its initial position when theswitch is rocked back to open position. The spring 5D is a considerablylighter spring than the spring 46 and its action is readily overpoweredby that of the spring 46 when the switch is released. The

'gear 41 is in mesh with a pinion '5| rigid with a gear 52, such gearand pinion forming a unit and being carried by the shaft 53. The gear 52meshes with a pinion 54 which is fast to the shaft 55. 'The shaft 55also rigidly carries a driving gear 56 which meshes with a pinion 51formed as a unitary structure with a flywheel 58. Either the flywheel 58or the unit consisting oi.' the pinion 5| and gear 52 may be loose onthe shaft 53, or if desired both may be loose on the shaft.

It will be seenthat when the switch is released by the outward droppingof the corresponding fuse unit, that the switch arm tends to movetowards closed position and drives the arm 48 of the time delaymechanism in a clockwise direction, thus rotating the flywheel 58. Inview of the inertia of the flywheel, it does not immediately come up tofull speed but gradually speeds up and thus provides a time delay forthe closing of the switch. The switch, therefore, is delayed in itsclosing stroke until the rounded portion 43 of the arm 42 passes by thearm 48 of the escapement mechanism at which time the switch makes a.quick nal closing stroke.

It is to be noted at this point that instead of having the switchcompletely released from the time delay mechanism as described, that theincreasing speed of the flywheel itself provides for an increasingclosing speed of the switch as the switch approaches its final position,but this is not the preferred arrangement. The preferred arrangement is,as stated above, to have the arm 42 pass by the arm 48, see Figui-el, sothat the switch will be free of restraint of the time delay mechanismand the final portion of the closing stroke of the switch will beextremely rapid.

Inplace of the flywheel 58 a simple type of fan construction indicatedat 59 in Figure 5 may be employed, or if desired other types ofmechanical escapement can be used than these shown, two

forms of mechanical escapement however being shown for the purpose ofillustration.

It is to be noted from reference to Figure 1 that the upper terminal 28carries a housing 60 which houses the pivoted portion oi' the switchtogether with its spring 46 as well as the time delay mechanism and theupper end of the fuse tube. Thishousing projects over the latch 21 andover the brush contacts 29 and over the contact portion 4| of theextension of the switch arm and thus adequately protects these partsfrom snow, ice and sleet.

It is customary to provide a shielding plate 6| formed integrally withthe lower collar I5 to afford limited protection at least for the linkI1 and brush contact I 3 and lower portion of the fuse stmcture.

The operation of the apparatus is as follows:

When the first fuse unit blows, the lever l1 is released and allows thelower end of the fuse tube to rock downwardly and outwardly and allowsthe upper end of the fuse tube to rock downwardly out of engagement withthe 'latch 21. .The fuse tube then drops outwardly and swings downwardlybelow the lower stationary contact.

When thefuse tube has dropped outwardly,

' it' no longer'restrains the extension or arm l! ofthe switch and theswitch under the biasing action of its spring 44 moves towards closedposition. In so doing. the extension or cam member 42, see Figure 1,drives the time delay mechanism which' causes the first portion at leastof the closing stroke of the switch to be relatively slow and thusprovides the time delay. Thereafter in the form shown, the roundedportion 42 finally rides past the arm 48 of the time delay mechanism andthe switch is then no longer restrained by such time delay mechanism andthus quickly closes,

connecting the electric line through the next fuse unit.

Obviously if the overload continues, the next fuse unit will drop out ofcircuit and release its transfer switch for connecting the third fuseunit in service. The third fuse unit is not' usually provided with atransfer switch unless a fourth fuse unit is to be added. Obviously asmany fuse units as needed could be employed.

Assume that the first fuse unit has blown and dropped outwardly anddownwardly and the transfer switch has functioned to connect the nextfuse unit in service. The blown fuse unit is readily detached from thehooks H by means of a switch stick engaging the portion Il of the fusetube, see Figure 1. The fuse tube is lifted down from position, isrefused, is replaced,A and is rocked back into service, the switchstick, after having positioned the fuse tube in place being detachedfrom the member Il and. hooked into the eyelet 24. Thereafter therefused tube is rocked back into position by means of a switch stick. Itengages the contact portion 4I of the extension 39 of the switch arm,see Figure 1, and rocks the switch arm back to open position as shown.This backward rocking of the switch arm to open position does not drivethe time delay mechanism and consequently no strain is imposed on thetime delay mechanism, although the refused fuse unit may be rocked backinto position in avery rapid manner. Obviously as the extension or cammember 42 of the switch arm is rocked in a clockwise direction from theposition shown in Figure 3 to the position shown in Figure 2, the timedelay mechanism will be automatically returned by means of its restoringspring 50, see Figure 4, and will ultimately come to rest with the arm42 thereof in engagement with the face 45 of the extension 42 of theswitch arm.

It is obvious that when the refused unit is rocked back into place, thatit does not open the. circuit for its upper contact 2l is in engagementwith the contact portion 4I of the extension 29 of the switch arm beforethe switch arm starts to move away from its closed position. In itsfinal position the upper contact 2| of the fuse tube engages the brushcontact 2l of the upper stationary terminal member and the fuse tube istemporarily locked in position. 1

It is obvious that any of the fuse units may be removed from serviceposition by pulling downwardly and outwardly on the eyelet 24 by meansof a'switch stick. When this is done, the arms 2C raise the latch 21 andrelease the upper end of the fuse tube, allowing the fuse tube to berocked outwardly without breaking the fuse link.

It is obvious that if the nrst or second fuse tubes were detachedmanually as described, that the corresponding ,transfer switch wouldultimately close to connect the next succeeding fuse in service.

It is to be understood that the flywheel Il, see Figure 4. or fan I8,see Figure 5, may be housed and protected from the weather in anysuitable manner. For instance, the housing I0 may have a cap 02 securedin place in any suitable manner to a cylindrical or other shapedextension l2 of the housing l0.

It is also clear from an examination of Figure A, that the housing i0may have an inturned front portion 20' whose inner end is spaced fromthe opposite wall of the housing to provide a space through which theswitch arm 32 can project, as shown in Figure l.

It will be seen that a simple type of repeating dropout fuse device hasbeen provided in which mechanical escapement time delay means isemployed for delaying the connecting of the next succeeding fuse unit inservice. It will also be seen that the switch is released by the outwardvdropping of the fuse tube of the corresponding fuse unit but that aportion at least of the closing stroke of the switch is retarded by thetime delay means.

It will be seen further that a very simple type of mechanical time delaymeans may be employed and that this time delay means is wholly automaticin its operation, restraining the switch during a portion at least ofthe closing motion of the switch and providing for the sudden release ofthe switch during the final portion of its closing stroke and also beingunstressed during the opening stroke of the switch due to the rocking ofthe refused unit back into service or operative position, the time delaymeans itself being provided with restoring means for restoring it to itsinitial position.

i Although this invention has been described in considerable detail, itis to be understood that such description is intended as illustrativerather than limiting, as the invention may be variously embodied and isto be interpreted as claimed.

We claim:

1. An automatic repeating fuse construction comprising a first fuse unitand a second fuse unit, each of said fuse units including a fuse tubehaving a discharge opening at one end, each of said fuse units beingnormally held in operative position, means for releasing said first fuseunit upon blowing of said first fuse unit, an electric line normallyconnected through said irst fuse unit, normally open switch meanspermanently biased towards closed position and located at a point remotefrom the open end of said first fuse unit for connecting said electricline through said second fuse unit upon blowing of said nrst fuse unit,and time delay means including a mechanically rotated member operativelyconnected to and rotated by said switch means a pluraiity of times whensaid switch means is moving towards closed position for a portion onlyof the closing stroke of said switch and being operatively free of saidswitch for the final portion of the closing stroke4 of said switch.

2. An automatic repeating fuse construction comprising a first fuse unitand a second fuse unit, each of said fuse units including a fuse tubehaving a discharge opening at the bottom. each of said fuse units beingnormally held in operative position, means for releasing said first fuseunit upon blowing of said first fuse unit, an electricline normallyconnected through said first fuse unit, normally open switch meanspermanently biased towards closed position and located atapointadjacentjhgllpler end of said repeating fuse construction for-connectingsaid electric line through said second fuse unit upon blowing of saidfirst fuse unit, and time delay means including a mechanically rotatedmember operatively connected to and rotated by said switch mean's aplurality of times when said switch means is moving towards closedposition' for a portion only of the closing stroke of said switch andbeing operatively free of said switch for the final portion of theclosing stroke of said switch.

3. An automatic repeating fuse construction comprising a first fuse unitand a second fuse unit, each of saidfuse units being normally held inoperative position, an electric line normally connected through saidfirst fuse unit,normally open transfer switch means for transferring theelectric circuit to the second fuse unit upon blowing of said first fuseunit, and mechanical escapement time delay means operatively connectedto said switch means and including a, revoluble member rotated aplurality of times when said switch means is moving towards closedposition, said switch means being restrained from closing motion by saidfirst fuse unit until said first fuse unit has blown and being releasedby said first fuse unit upon blowing thereof, said mechanical escapementtime delay mechanism controlling said switch means and said switch meanshaving a closing stroke, the first portion of which being retarded bythe mechanical esv of the closing stroke of capement time delay meansand the last por- Ition being free of 4. An automatic said time delaymeans. repeating fuse construction comprising a first fuse unit and asecondffuse unit, each of said fuse units being normally held inoperative position, an electric line normally connected through saidfirst fuse unit, normally open transfer switch means for transferringthe electric circuit to the second fuse unit upon blowing of said firstfuse unit, and mechanical escapement time delay means operativelyconnected to said switch means, said switch means being restrained fromclosing motion by said first fuse unit until said first fuse unit hasblown and being released by said first fuse unit upon blowing thereof,said mechanical escapement time delay mechanism controlling said switchmeans, the first portion atleast of the closing motion of said switchmeans being retarded by the mechanical escapement time delay means, saidswitch means being operatively free from the retarding action of.' saidmechanical escapement time delay means during the latter part of thestroke of said switch means and making a quick final closing motionduring said latter part of the closing stroke of said switch means.

5. An automatic repeating fuse construction comprising a first fuse unitand a second fuse unit, an electric line normally connected through saidfirst fuse unit, switch means for connecting said electric line throughsaid second fuse unit upon blowing of said first fuse unit, biasingmeans biasing said switch means towards closed position, said switchmeans being normally held in open position by said first fuse unit andbeing released upon blowing of said first fuse unit, and mechanicalescapement means driven .by the vclosing stroke of said S biasing meansof said switch means and delaying the closing motion of said switchmeans when said switch means is released, said escapement means havingself-restoring means.

6. An automatic repeating fuse construction comprising a. first fuseunit and a second fuse unit, an electric liiie normally connectedthrough said first fuse unit, switch means for connecting said electricline through said second fuse unit upon blowing of said first fuse unit,biasing means biasing said switch means towards closed position, saidswitch means being normally restrained by said first fuse unit and beingreleased upon blowing of said first fuse unit, and mechanical escapementtime delay means driven by said biasing means when said switch means isreleased and including a rotary member whose rotation lis retarded, saidmechanical escapement means being operatively free of said switch duringthe final portion of the closing stroke of said switch.

7. An automatic repeating fuse construction comprising a first fuse unitand a second fuse unit, an electric line normally connected through idfirst fuse unit, switch means for connecting said electric line throughsaid second fuse unit upon blowing of said first fuse unit, biasingmeans biasing said switch means towards closed position, said switchmeans being normally restrained by said first fuse unit and beingreleased upon blowing of said first fuse unit, and time delay means forretarding a portion at least said switch means, said time delay meanscomprising a rotary member and a gear train interposed between saidrotary member and said switch means, said gear train being driven fromsaid switch means and driving said rotary member, said time delay meanshaving self-restoring means. I 8. An automatic repeating fuseconstruction comprising a first fuse unit and a second fuse unit, anelectric line normally connected through said first fuse unit, switchmeans for connecting. said electric line through said second fuse unitupon blowing of said first fuse unit, biasing means biasing said switchmeans towards closed position, said switch means being normallyrestrained by said rst fuse unit and being released upon blowing of saidfirst fuse unit, and time delay means for delaying a portion of theclosing stroke of said switch means, said time delay switch means, saidswitch delay means during the final portion of the closing stroke ofsaid switch.

9. An automatic repeating fuse construction comprising a first fuse unitand a second fuse unit, an electric line normally connected through saidfirst fuse unit, switch means for connecting said electric line throughsaid second fuse unit upon blowing of said first fuse unit, biasingmeans biasing said switch means towards closed position, said switchmeans being normally restrained by said Iirst fuse unit and beingreleased upon blowing of said first fuse unit, and time delay means fordelaying a portion of the switch means, said time delay means includinga fan driven from said switch means, said switch being free of said timedelay means during the final portion of the closing stroke of saidswitch.

10. An automatic repeating fuse construction comprising a first fuseunit and a second fuse unit, each of said fuse units including a fusetube normally held in operative position, means unit. and mechanicaltime delay means delaying a part o! the clodng stroke o! said switchmeans, said mechanical time delay means including a rotary member drivenfrom said switch means. said switch being free of said time delay meansduring the iinal portion of the closing stroke of said switch.

11. An automatic repeating fuse construction comprising a ilrst fuseunit and a second fuse unit, each of said fuse units including a iusetube normally held in operative pomtion. means for releasing the fusetube oi' said first fuse unit upon blowing ot said iirst Iuseunit, anelectric line normally connected through said iirst fuse unit, normallyopen switch means permanently biased towards closed position and havingan arm normally in engagement with said nrst fuse unit and beingrestrained againstclosing motion by said ilrst fuse unit and beingreleased when the fuse tube of said ilrst fuse unit drops out ofoperative position upon blowing oi! said iirst fuso unit, and mechanicaltime delay means delaying a part of the closing stroke 'of said switchmeans and being inoperatively related to said switch during the ilnalportion 'of the closing stroke of said switch, said mechanical timedelay means including a rotary member driven by said switch means l2. Anautomatic repeating fuse construction comprising a ilrst fuse` unit anda second fuse unit, each of said fuse units including a fuse tube havinga discharge opening at the bottom. each of said fuse units beingnormally held in operative position, means for releasing said ilrst fuseunit upon blowing oi' said first fuse unit to allow said first fuse unitto drop out ot operative position, an electric line normally connectedthrough said iirst fuse unit, normally open switch means normally biasedtowards closed position and located adjacent the upper end of said ilrstfuse unit for connecting said electric line through said second fuseunit'upon blowing of said ilrst fuse unit, mechanical escapement timedelay means including a. rotary member for delaying a portion o! theclosing stroke oiv said switch means; and means operatively connectingsaid time delay means and said switch means during a portion of theclosing stroke ot said switch means to drive said rotary member fromsaid switch means and inoperatively relating said switch means to saidtime delay means during the ilnal portion of the closing stroke of saidswitch means.

=13.An automatic repeating fuse construction comprising a ilrst fuseunit and a second fuse unit. an electric line normally connected throughsaid iirst fuse unit, switch means for connecting said electric linethrough said second i'use unit upon blowing of said ilrst fuse unit,biasing means biasing said switch means towards ,closed position, saidswitch means being normally restrained by said rst fuse unit and beingreleased upon blowing of said first fuse unit, and time delay m'eans,said time delay means including restraining means for preventingimmediate closing of said switch means after blowing of said rst fuseunit and a rotary member for controlling the motion of said restrainingmeans, said time delay means having self-restoring means for returningsaid time delay means .to its original position when said switch ismoved to open position.

'14. An automatic repeating fuse construction comprising a first fuseunit and a second fuse unit, an electric line normally connected throughsaid first fuse unit, switch means for connecting said electric linethrough said second Iuse unit upon blowing of said iirst fuse unit,biasing means biasing said switch means towards closed position, saidswitch means being normally held in open position by said iirst fuseunit and being released upon blowing of said first fuse unit, me-

chanical escapement means driven by the biasing means of said switchmeans and delaying the closing motion of said switch means when saidswitch means is released, and biasing means for returning saidmechanical escapement means to its original position when said switchmeans is moved to open position.

WILLIAM O. SCHULTZ. ALWI'N G. STEINMAYER.

